Triglyceride-glucose index in non-obese individuals:its association with and predictive value for non-alcoholic fatty liver disease
Objective To investigate the association of triglyceride-glucose index(TyG)with non-alcoholic fatty liver disease(NAFLD)and its diagnostic value for NAFLD in non-obese individuals.Methods We retrospectively collected the data of non-obese individuals(BMI<25 kg/m2)undergoing routine health examination at Second Affiliated Hospital of Xi'an Jiaotong University between May,2020 and December,2023,who all received abdominal ultrasound examination for NAFLD screening.The nonlinear relationship between TyG and non-obese NAFLD was explored using restricted cubic splines(RCS),and LASSO regression was used for variable screening;the correlation between TyG and NAFLD risk was analyzed using multivariate logistic regression.The diagnostic value of TyG for non-obese NAFLD was assessed using receiver-operating characteristic(ROC)curves and sensitivity analysis.Results A total of 3723 non-obese subjects were enrolled in this study,including 432(11.6%)patients with NAFLD.Compared with the healthy individuals,the patients with NAFLD had significant elevations of systolic and diastolic blood pressures,total cholesterol,triglycerides,LDL-C,blood uric acid,fasting blood glucose,and TyG index and a decreased HDL-C level(P<0.05).Multivariate logistic regression revealed that for each one-unit increase of TyG,the risk of non-obese NAFLD increased by 2.2 folds(OR=3.22,95%CI:2.53-4.12,P<0.001).Compared with a TyG index in the lowest quartile Q1,a TyG index in the Q2,Q3 and Q4 quartiles was associated with an increased risk of NAFLD by 1.52 folds(OR=2.52,95%CI:1.20-5.95),3.56 folds(OR=4.56,95%CI:2.28-10.46),and 8.66-folds(OR=9.66,95%CI:4.83-22.18),respectively.The RCS curve demonstrated a significant linear correlation between TyG index and non-obese NALFD risk(P for nonlinear=0.019).For diagnosing non-obese NALFD,TyG index had an area under ROC curve of 0.819 with a sensitivity of 78.0%and a specificity of 71.2%.Conclusion An increase of TyG index is correlated with increased risks of NAFLD in non-obese individuals and can serve as an indicator for screening early NAFLD in healthy individuals.